Transport evidence for Fermi-arc mediated chirality transfer in the Dirac semimetal Cd$_3$As$_2$

TL;DR

This study demonstrates Fermi-arc mediated chirality transfer in the Dirac semimetal Cd$_3$As$_2$ through transport measurements, revealing Weyl orbits and topological charge dynamics, advancing understanding of topological semimetals.

Contribution

It provides experimental evidence of Fermi-arc mediated Weyl orbits in Cd$_3$As$_2$, linking surface states with bulk chiral dynamics in a transport setting.

Findings

Observation of Shubnikov-de Haas oscillations involving Fermi Arc states

Magnetic field periodicity depends on sample thickness

Evidence for Weyl orbits connecting surface and bulk states

Abstract

Dirac semi-metals show a linear electronic dispersion in three dimension described by two copies of the Weyl equation, a theoretical description of massless relativistic fermions. At the surface of a crystal, the breakdown of fermion chirality is expected to produce topological surface states without any counterparts in high-energy physics nor conventional condensed matter systems, the so-called "Fermi Arcs". Here we present Shubnikov-de Haas oscillations involving the Fermi Arc states in Focused Ion Beam prepared microstructures of Cd$_3$As$_2$. Their unusual magnetic field periodicity and dependence on sample thickness can be well explained by recent theoretical work predicting novel quantum paths weaving the Fermi Arcs together with chiral bulk states, forming "Weyl orbits". In contrast to conventional cyclotron orbits, these are governed by the chiral bulk dynamics rather than the common momentum transfer due to the Lorentz force. Our observations provide evidence for direct access to the topological properties of charge in a transport experiment, a first step towards their potential application.